Estimation of lumbar disc areas by means of anthropometric parameters.

In order to standardize the results of different biomechanical studies concerning stresses on lumbar discs, it may be useful to estimate the disc dimensions of the examined subjects and to refer the stress values to a unit surface area (square centimeter). The association between anthropometric parameters and discal areas at the L3-L4, L4-L5 and L5-S1 levels, examined by computed axial tomography, was studied in a group of 32 subjects (16 male; 16 female) with the aim of estimating lumbar disc areas with a simple method. Bony structure weight, which is computed by an equation that takes into account the diameters of the wrist, elbow, knee, and ankle and the stature, is the anthropometric parameter best associated with the areas of lumbar discs. The wrist diameter also shows a good association with the same areas. On the contrary, the association between body weight and disc areas was found to be less adequate for this purpose. The equations of the relative regression lines are reported as well as the criteria for their practical applications.